True or Poo?

HOODED SEALS USE BALLOONS TO ATTRACT MATES

TRUE OR POO? TRUE

When humans think of balloons, they might think of birthday parties, but when a female hooded seal (Cystophora cristata) sees a balloon, she is more likely to think of mating. Hooded seals are so-named because of the presence of a “hood”—an inflatable bladder between the eyes and upper lip, found on males. Males inflate their “balloons” to make themselves appear larger and more threatening toward other males, in the hope of exerting their dominance. But that’s not all, male hooded seals also have an inflatable nasal membrane that appears bright red or pink when inflated. If the display fails to intimidate, males may resort to fighting to decide on their social standing. But his work isn’t done yet—he also presents his balloon to a female, hoping to impress her enough that she will agree to mate with him. Given this rather strange mating ritual, we do not recommend that you invite hooded seals to a child’s birthday party.

INFANT HOOFED MAMMALS CAN WALK WITHIN MINUTES OF BEING BORN

TRUE OR POO? TRUE

Humans generally start walking a year after they are born, but giraffes, elephants, and other hoofed mammals accomplish this “feet” within minutes. This doesn’t mean that humans are worse parents than other mammals, but rather it has to do with our brains. Humans have large brains for our size and subsequently a large cranium, or skull. For our species’ existence this is a very good thing; we can use tools, solve complex problems, communicate, and even write books about farts and poo. But those large skulls need to be able to fit through the birth canal, so our brains are relatively underdeveloped at birth, which means that a good portion of our development happens afterwards. The brains of hoofed mammals, on the other hand, are relatively more advanced than humans’ by the time they’re born. Their gestation—the time between conception and birth—is typically longer, at around 14 months for a giraffe and as long as 22 months for an elephant. In fact, scientists have found that the time it takes for a given species of mammal to walk from conception (including gestation) is well predicted by the average size of that species’ brain.

CAPUCHIN MONKEYS USE THE SCENT OF URINE FOR COURTSHIP

TRUE OR POO? TRUE

There are numerous similarities between humans and other primates, including our genetic makeup, our use of tools and our propensity to socialize with other members of our species. Likewise, we can find similarities between humans and capuchin monkeys (subfamily Cebinae), which can be found in forested areas in Central and South America. To get a male’s attention, female capuchins will often grab or pull his tail or may even throw rocks at him; behaviors that are reminiscent of schoolyard children. However, one behavior that capuchins and (most) humans do not share is that male capuchins will urinate into their hands and then rub it into their fur. It may seem gross, but there’s a good reason for this urine wash. Studies have found that females are able to detect testosterone levels in the urine, which allows them to identify sexually mature males and differentiate potential mates based on their social status. At this point, we are unaware of a similar ability in humans to use the scent of urine to distinguish potential mates, so we advise against using a urine-based aftershave.

FLATWORMS FIGHT AND STAB EACH OTHER WITH THEIR GENITALIA

TRUE OR POO? TRUE

The interactions between species can often be described as an “evolutionary arms race,” in which evolutionary adaptations in one species are eventually countered by adaptations in another. For example, rough-skinned newts (Taricha granulosa) have evolved the secretion of a toxin that can cause paralysis and death, but some garter snakes (Thamnophis sirtalis), which eat newts, are resistant to it. But for many species, like flatworms (phylum Platyhelminthes), an ongoing evolutionary arms race is happening within a species.

Hermaphroditic flatworms, where each individual is equipped with both egg- and sperm-producing organs, will fence each other with their penises, which are extendable and sharp—the longer and sharper the better. The winner will then stab the loser and inject them with their sperm. This is known as traumatic insemination, and it can be observed throughout the animal kingdom in species such as rotifers, gastropod snails, nematodes, and the giant squid. Traumatic insemination has evolved in species that had pretty gross mating behavior in the first place, like males that glue the female’s reproductive tract closed, or block it with their own reproductive organs in the hope of preventing other males reproducing with her. By piercing and injecting the female with their hypodermic genitalia, competing males can then sidestep this barrier.

OCTOPUSES HAVE DETACHABLE PENISES

TRUE OR POO? TRUE

What would you do if the female of your species was five times your size and could strangle and eat you when you attempted to mate with her? If you answered “detach your penis and throw it at her,” you might just be an argonaut (genus Argonauta). Argonauts are a genus of octopuses that can be found in the open ocean, and they are distinguished from other octopuses in that they produce their own shell. The male argonaut’s “penis” is actually a modified arm, known as a hectocotylus, that contains sperm. When removed from the male’s body, this appendage continues to swim toward the female, attaches to her mantle (the structure behind their head where you can find their organs), and can be stored in her mantle cavity. Unfortunately for the male, he dies shortly afterwards (so would you, if you ripped one of your arms off and floated off into the ocean), so he only gets one shot at siring offspring. Females, on the other hand, can store sperm and fertilize her eggs from multiple males.

While it might seem to be a rather unfortunate fate for the male argonaut, the alternative is being eaten without the chance to pass along his genes to the next generation, which is even less ideal.

DUNG BEETLES CAN PUSH A BALL OF POO OVER 1000 TIMES THEIR OWN BODY WEIGHT

TRUE OR POO? TRUE

This awesome superfamily of insects—the scarab beetles or dung beetles, Scarabaeoidea—all feed partly or exclusively on feces. It may not sound very appetizing, but they do an incredibly important job of recycling nutrients—without them there would be poo all over the place! And that would lead to an increased spread of disease and poor soil quality. There are three types of dung beetle: dwellers, who just hang out in the dung where they find it; burrowers, who tunnel under the dung and bury it; and rollers, which form the dung into balls before rolling it away to their burrows and breeding chambers. This third group go to some extreme lengths to get this poopy food ready for their babies to eat. The male shapes the feces into a huge ball and starts rolling it toward soft ground. If the female likes what she sees (and who wouldn’t?), she will climb onto and ride the ball—adding her own weight to what he is pushing (helpful!). Once they get to a good spot, they both bury the ball and prepare it for brooding, then the female lays her eggs in it. One species in particular, Onthophagus taurus, is particularly good at pushing around big balls of poo—males can push up to 1142 times their own weight. That would be the equivalent of a human rolling a ball the weight of a sperm whale. Talk about a strong father figure!

MALE SEAHORSES GET PREGNANT

TRUE OR POO? MOSTLY TRUE

For all 54 known species of seahorses (genus Hippocampus), the male is observed giving birth to the young, but does that mean the male gets pregnant? While we have rated this statement as “true,” male seahorses don’t become pregnant in the manner in which most people are familiar—they aren’t actually producing eggs. Male seahorses are equipped with a brood pouch on their abdomen, and after successfully courting the female with a dance, she will deposit eggs into this pouch. While scientists don’t know the exact cause for this parental role reversal, it is possible that this trait evolved because it allowed females to produce more eggs; handing over the reins to the male means more time for her to devote to producing the next batch. After being fertilized by the male, the eggs will develop within this pouch and eventually he will give birth to the young–which are fully formed, tiny versions of the adults.

Male seahorses, however, contribute more than just a pouch for developing embryos, studies have shown that they provide nutrients, remove waste and even protect their young from infection. Interestingly, the genes that are expressed during a male seahorse’s pregnancy are similar to those found in pregnant mammalian females. However, unlike mammals, seahorse young can develop outside of the brood pouch, although this process typically takes longer, and fewer offspring survive.

SOME ANIMAL OFFSPRING EAT THEIR WAY OUT OF THEIR MOTHER

TRUE OR POO? TRUE